Jeff set up his championship season, which earned him the distinction, with older brother David Green, of becoming the first brother combination to win series titles; with a second place finish in the championship behind Dale Earnhardt Jr. in 1999, despite missing one race.
Jeff absolutely steamrollered the competition in 2000 to win his first Busch Series championship in record setting fashion posting a series best six wins, seven poles, 25 top-five and 27 top-10 finishes, which broke the all-time series record for top-fives in a season. His margin of victory over ppc Racing teammate Jason Keller was the biggest championship point margin (616) in series history.
Prior to 2001, Jeff had made 50 starts in five different seasons for a variety of owners, but the RCR team was his best opportunity ever in the Cup Series. Making eight starts for Childress, Jeff showed his potential by winning the pole for the Sharpie 500 at Bristol Motor Speedway, and starting inside the top-20 for five of his eight starts, and a best finish of ninth place at Homestead. Jeff also defended his Busch Series title but ended up second to champion Kevin Harvick after winning four races and one Bud Pole.
In 2002, Jeff was surprisingly the class of the RCR Winston Cup stable, finishing ahead of teammates Kevin Harvick and Robby Gordon in the series standings by scoring four top-five finishes and ended up 17th in the points total. While Jeff is still searching for his first Winston Cup victory, he posted a career-best second-place finish at New Hampshire in September despite a dismal 30th-place starting spot.
